1. Field of the Invention
The invention herein pertains to a self-cleaning steam iron using a dumper valve to empty the tank suddenly onto the soleplate to purge the iron and, more particularly, to the structure of a preassembled subunit dumper valve assembly that is easily installed in the tank bottom.
2. Description of the Prior Art
In steam irons a water tank is used above the soleplate and a water valve structure provides controlled water drippage into the steam generator where it is flashed into steam and directed out soleplate ports to steam the article. Generally, the user is advised to use distilled water because of the fineness of various water passages and orifices which tend to clog due to mineral deposits from the water, which varies locally. In especially hard water localities, tap water contains minerals which produce loose flakes and deposits that plate out easily onto hot iron components. These are generally lime or calcium carbonate as well as other chemicals in solution or in a colloidal suspension. Self-cleaning irons have appeared such as shown in U.S. Pat. Nos. 3,747,241 and 3,823,498 both of common assignment where the tank water, by a dumper valve is suddenly emptied onto the hot soleplate and into the boiler generator respectively to purge and scrub out the iron prying out the loose deposits and other debris. Other designs blow an extra charge of high pressure steam through the soleplate ports cleaning only the ports. Part of the new self-cleaning concept of applicant's assignee includes cleaning the valve structure per se by a constant scraping action to remove deposits which are then carried out of the iron by the self-cleaning action of the 3,747,241 patent. The two together, purging the tank and passages plus the valve structure cleaning, have provided a self-cleaning iron with much longer life than previously obtainable. The scraping concept of the metering rod and orifice of the valve structure is disclosed in U.S. Pat. No. 3,496,661 of common assignment. The present invention is directed to an improvement in the dumper valve assembly to provide a unitary assembly of few parts that is self-contained and easily assembled as a complete subunit in an iron water tank.